This invention relates generally to lawn mowers and more particularly to a safer cutting assembly for mounting on a power mower having a vertical drive shaft.
The dangers of conventional rotary mowers having steel blades are well known. As shown in U.S. Pat. No. 4,065,913 to Fisher et al. which issued Jan. 3, 1978, it is known to overcome some of these problems by providing a mower cutting assembly having a plastic rotary disc. As also shown in Canadian patent no. 1,079,076 to Scanland et al. which issued June 10, 1980, and U.S. Pat. Nos. 4,126,991 to Goblin et al. which issued Nov. 28, 1978 and 4,382,356 to Ballas, Sr. et al. which issued May 10, 1983, it is also known to provide flexible cutting pins to reduce the danger of injury. More recently, Canadian patent no. 1,190,753 shows the use of flat plastic cutting blades extending from a central disc. However, it has been found that all of the prior art cutting assemblies have the disadvantage that they do not adequately balance the need for flexibility of the cutting blades for safety with the need for rigidity of the cutting blades to effectively cut the grass.
It is also known from prior art such as Canadian patent no. 1,101,226 to Hetrick which issued May 19, 1981 and U.S. Pat. No. 4,301,642 to Thurber which issued Nov. 24, 1981 to mount air impeller vanes on top of the disc to create a forceful air flow to blow the cut grass out the side chute of the mower. However, these prior vanes have the disadvantage that they can throw stones or other hard objects out of the side chute at a very dangerous velocity.